Document static multicast filter usage

[jovatn]

Infix supports configuring static multicast entries (infix-bridge.yang), but there does not seem to be any CLI examples in the documentation.

Perhaps add it after (or within) the section on IGMP/MLD Snooping.

$ pyang -f tree infix-if-bridge.yang 
...
  augment /if:interfaces/if:interface:
    +--rw bridge
       +--rw ieee-group-forward*        ieee-reserved-groups
       +--rw (type)?
          +--:(ieee8021d)
          |  +--rw multicast!
          |  |  +--rw snooping?         boolean
          |  |  +--rw querier?          querier-mode
          |  |  +--rw query-interval?   uint16
          |  +--rw multicast-filters!
          |     +--rw multicast-filter* [group]
          |        +--rw group    union
          |        +--rw ports* [port]
          |           +--rw port     if:interface-ref
          |           +--rw state?   mdb-state
          +--:(ieee8021q)
             +--rw vlans! {vlan-filtering}?
                +--rw proto?   dot1q-types:dot1q-tag-type
                +--rw vlan* [vid]
                   +--rw vid                  dot1q-types:vlanid
                   +--rw multicast!
                   |  +--rw snooping?         boolean
                   |  +--rw querier?          querier-mode
                   |  +--rw query-interval?   uint16
                   +--rw multicast-filters!
                   |  +--rw multicast-filter* [group]
                   |     +--rw group    union
                   |     +--rw ports* [port]
                   |        +--rw port     if:interface-ref
                   |        +--rw state?   mdb-state
                   +--rw untagged*            if:interface-ref
                   +--rw tagged*              if:interface-ref

[troglobit]

CCB decision: Do as part of #649.